Recently, in an X-ray diagnostic apparatus for circulatory organs, with increases in the number of examinations and treatment time in association with intervention, exposure of patients to X-rays poses a problem. For this reason, the X-ray diagnostic apparatus sometimes displays a reference air kerma as an index for the exposure dose to a patient, on the irradiation side of X-rays generated by an X-ray tube, based on an output from an area dosimeter. In addition, dose information based on DICOM RDSR (Radiation Dose Structure Report) is standardized and output to the outside. That is, the skin dose to the object is calculated based on an output from the area dosimeter.
However, the dose information using the output from the above area dosimeter represents a total dose but does not represent a PSD (Peak Skin Dose) as important dose information concerning the object. For this reason, a conventional X-ray diagnostic apparatus has a problem that it is not possible to accurately display a local exposure risk concerning an object. In order to solve this problem, the X-ray diagnostic apparatus has, for example, a dose map function of displaying a skin dose integration value estimated concerning an object on a patient model in color. In general, however, the dose map function also uses an output from the area dosimeter.
The area dosimeter has a problem that it can only acquire an integral area dose at predetermined time intervals due to a problem of output responsiveness. This makes it impossible to accurately acquire a dose for each time of X-ray irradiation to an object.
As described above, the X-ray diagnostic apparatus including the dose map function and the area dosimeter cannot accurately calculate a skin dose to an object when performing, for example, rotational imaging and panning operation in which an irradiation position changes during an irradiation period, and hence cannot generate a useful dose distribution as an index for exposure of the object.